Pathophysiology Lessons 3 and 4: RAAS, Electrolyte & Acid-Base Balance, Cellular Injury, Genetics, and Fluid Dynamics

Comprehensive vocabulary flashcards covering RAAS mechanisms, pharmacology, electrolyte imbalances, acid-base disorders, cellular injury, familial genetics, plasma proteins, Starling forces, and edema types based on Pathophysiology Lessons 3 and 4.

Renin-Angiotensin-Aldosterone System (RAAS)

A hormonal system that regulates blood pressure, blood volume, and sodium balance, activated when the body senses decreased blood pressure, blood volume, sodium levels, or renal perfusion, or increased sympathetic stimulation.

Renin

An enzyme released into the bloodstream by the juxtaglomerular apparatus (JGA) in the kidneys when low blood pressure, low blood volume, or low sodium is detected.

Angiotensinogen

An inactive protein constantly produced by the liver that is cleaved by renin to form Angiotensin I.

Angiotensin-Converting Enzyme (ACE)

An enzyme primarily located in the lungs that converts inactive Angiotensin I into active Angiotensin II.

Angiotensin II

A potent peptide hormone that restores blood pressure by causing systemic vasoconstriction and stimulating the release of aldosterone from the adrenal glands and ADH from the posterior pituitary.

Aldosterone

A hormone secreted by the adrenal glands that acts directly on the kidneys to retain sodium and water while pumping out potassium.

Anti-Diuretic Hormone (ADH)

Also known as vasopressin, a hormone synthesized by the hypothalamus and released from the posterior pituitary that promotes reabsorption of water from urine back into the bloodstream.

Osmoreceptors

Sensory receptors located in the hypothalamus that detect changes in solute concentration and water balance in the body.

Baroreceptors

Pressure sensors located in the carotid sinus and aortic arch that detect drops in circulating blood pressure and volume.

ACE Inhibitors

Medications such as ramipril, lisinopril, and enalapril that block the conversion of Angiotensin I to Angiotensin II; a notable side effect is a persistent dry cough caused by bradykinin accumulation.

Angiotensin Receptor Blockers (ARBs)

Medications such as losartan, valsartan, and candesartan that block Angiotensin II receptors to reduce vasoconstriction and aldosterone release without causing a dry cough.

Aldosterone Antagonists

Potassium-sparing medications such as spironolactone and eplerenone that block aldosterone action in the kidneys, decreasing sodium/water reabsorption and increasing potassium retention.

Angiotensin Receptor-Neprilysin Inhibitor (ARNI)

A combination medication (such as sacubitril/valsartan) used in heart failure with reduced ejection fraction that blocks Angiotensin II receptors while enhancing natriuretic peptide activity.

Hyperkalemia

Abnormally elevated potassium levels in the blood, often caused by aldosterone blockade or renal insufficiency, which can disrupt cardiac conduction and lead to dangerous dysrhythmias.

Hypokalemia

Abnormally low blood potassium levels, which can result from pathologically elevated aldosterone levels and lead to cardiac conduction abnormalities.

Hypocalcemia

Abnormally low calcium levels in the blood, causing increased nerve and muscle excitability that manifests as twitching, cramps, and seizures.

Hypercalcemia

Abnormally high calcium levels in the blood that lead to muscle weakness, confusion, and lethargy.

Hypophosphatemia

Abnormally low phosphate levels in the blood, characterized by muscle weakness, fatigue, confusion, and impaired cellular energy production.

Hyperphosphatemia

Abnormally high phosphate levels in the blood that can contribute to low calcium levels, muscle spasms, and calcium deposits in tissues.

Hypomagnesemia

Abnormally low blood magnesium levels that cause muscle cramps, tremors, weakness, and cardiac dysrhythmias.

Hypermagnesemia

Abnormally high magnesium levels in the blood, almost always resulting from kidney insufficiency, causing decreased reflexes, muscle weakness, and potential respiratory paralysis or cardiac arrest.

pH

The measurement of hydrogen ion ($H^+$) concentration in a solution, with normal arterial blood balance ranging strictly from $7.35$ to $7.45$.

Bicarbonate Buffer System

A biological buffer system where excess acid ($H^+$) combines with bicarbonate ($HCO_3^-$) to form carbonic acid ($H_2CO_3$), which rapidly dissociates into water and carbon dioxide ($CO_2$) to be exhaled.

Acidosis

A clinical condition where blood $pH$ falls below $7.35$, causing neurons to become less excitable, central nervous system depression, and potential failure of respiratory centers.

Alkalosis

A clinical condition where blood $pH$ rises above $7.45$, leading to neuronal hyperexcitability, sensory changes (numbness, tingling), muscle twitches, and potential respiratory muscle paralysis.

Metabolic Acidosis

An acid-base disturbance caused by accumulation of abnormal acids in the blood (e.g., in sepsis or DKA) where $PaCO_2$ is initially unaffected; compensated for by hyperventilation.

Kussmaul Respirations

A compensatory hyperventilation pattern seen in patients with Diabetic Ketoacidosis (DKA) where deep, rapid breathing functions to blow off excess $CO_2$ and reduce acidosis.

Metabolic Alkalosis

An acid-base condition resulting from a buildup of excess metabolic base (e.g., chronic antacid ingestion) or loss of normal acid (e.g., vomiting); compensated for by slowing ventilation.

Respiratory Acidosis

An acid-base disorder occurring when $CO_2$ retention increases $PaCO_2$ levels, typically during hypoventilation (e.g., narcotic overdose) or chronic lung diseases (e.g., Asthma, COPD).

Respiratory Alkalosis

An acid-base disorder caused by hyperventilation and excessive blowing off of $CO_2$, resulting in decreased $PaCO_2$; seen in PE, MI, sepsis, and DKA.

Arterial Blood Gas (ABG)

A diagnostic blood panel evaluating arterial parameters, with normal ranges: $pH$ ($7.35-7.45$), $PaCO_2$ ($35-45\,\text{mmHg}$), $PaO_2$ ($80-100\,\text{mmHg}$), $HCO_3^-$ ($22-26\,\text{mEq/L}$), and $O_2\,\text{Sat}$ ($95-100\%$).

Hypoxia

A state of cellular oxygen deprivation caused by reduced atmospheric oxygen, hemoglobin dysfunction, decreased red blood cell count, or respiratory/cardiovascular disease.

Ischemia

A specific form of cellular hypoxia resulting directly from a lack of blood supply to tissues.

Apoptosis

Genetically programmed normal cell death ("cell suicide") required for proper tissue function, aging, early development, menses, and removal of abnormal cells.

Necrosis

An irreversible pathological process in which cells die and break down within living tissues following unrecoverable injury.

Coagulative Necrosis

A pattern of necrotic cell death characterized by preserved tissue architecture and a firm texture, typically seen in heart or kidney infarctions.

Liquefactive Necrosis

A pattern of cell death where tissue is digested into liquid pus, characteristic of brain infarctions or abscesses.

Fat Necrosis

A type of tissue necrosis producing chalky white deposits from fat saponification, classically occurring in the pancreas.

Gangrenous Necrosis

A form of cell death resulting from a combination of coagulative and liquefactive necrosis, typically presenting as a blackened limb.

Endogenous Pyrogens

Fever-causing chemicals synthesized and released by host white blood cells in response to infection, inflammation, or tissue injury.

Virulence

The quantitative measure of the disease-causing ability of a microorganism.

Pathogenicity

The qualitative ability of a microorganism to cause disease in a host.

Incidence

The frequency of new disease occurrence within a specific population.

Prevalence

The total number of existing disease cases within a population over a specified timeframe.

Mortality

The number of deaths caused by a specific disease in a given population.

Autosomal Recessive

A genetic inheritance pattern where an individual must inherit two copies of a particular mutated gene to express the trait or disease.

Autosomal Dominant

A genetic inheritance pattern requiring an individual to inherit only one copy of a mutated gene to express the trait or disease.

Benign Tumor

A noncancerous, slow-growing, and localized cellular growth that does not invade adjacent tissues.

Malignant Tumor

A cancerous, fast-growing growth that invades nearby tissues and possesses the ability to metastasize throughout the body.

Sodium-Potassium Pump

A primary active transport membrane protein that hydrolyzes $1$ ATP molecule to transport $3\,Na^+$ ions out of the cell in exchange for $2\,K^+$ ions brought inside, maintaining resting membrane potentials and controlling intracellular volume.

Albumin

The most abundant plasma protein synthesized by the liver; maintains osmotic pressure to hold water inside blood vessels, transports substances, and acts as a buffer.

Globulins

A group of plasma proteins produced by the liver and immune system involved in immune defense (antibodies/immunoglobulins), substance transport, and blood clotting.

Fibrinogen

A liver-produced plasma protein essential for blood clotting that is converted into fibrin by thrombin to form a meshwork trapping platelets.

Prothrombin

A liver-synthesized plasma precursor protein that gets converted to active thrombin during blood clotting activation.

Capillaries

The smallest blood vessels in the human body that connect the arterial system to the venous system and allow transfer of gases, nutrients, and waste.

Starling Forces

The four hydrostatic and colloidal oncotic pressures (capillary hydrostatic, capillary oncotic, tissue hydrostatic, tissue oncotic) that govern fluid movement across capillary membranes.

Capillary Hydrostatic Pressure

The physical fluid pressure inside a capillary that pushes water and dissolved solutes out of the vessel into the interstitial tissue space.

Capillary Colloidal Oncotic Pressure

The osmotic pulling force exerted by plasma proteins (predominantly albumin) that draws water out of tissue spaces back into capillaries.

Peripheral Edema

Swelling caused by excess fluid collection in tissue spaces of lower extremities or hands, caused by increased capillary hydrostatic pressure, decreased oncotic pressure, or lymphatic obstruction.

Pitting Edema

A type of peripheral swelling in which pressing a finger into the swollen tissue leaves a temporary indentation or pit.

Sacral Edema

A dependent form of fluid buildup around the sacrum, occurring in bedbound patients because gravity causes fluid to accumulate in the lowest dependent areas.

Ascites

An abnormal accumulation of fluid within the abdominal (peritoneal) cavity, most commonly caused by liver cirrhosis leading to portal hypertension and hypoalbuminemia.